Chusetts



2 Sheets-Sheet 2' (No Model.)

J. E. WARREN & F; A.

OLOUDMAN.

A APPARATUS FOR THE RECOVERY OF SODA. No. 380,670. Patented Apr. 3,1888.

- INVENTIIIRS @707c7vE, wan rem 'frmca's 623 640mm 3 WATNEEEEE wczwwUNITED STATES PATENT OFFICE.

JOHN E. \VARREN AND FRANCIS A. GLOUDMAN, OF CUMBERLAND MILLS, MAINE,ASSIGNORS TO S. D. WARREN & COMPANY, OF BOSTON, MASSA- OHUSETTS.

APPARATUS FOR THE RECOVERY OF SODA.

$PECIFICATION forming part of Letters Patent No. 880,670, dated April 3,1888.

Application filed April 22, 1887. Serial No. 235,765. (No model.)

To all whom it may concern.-

Be' it known that we, JOHN E. \VARREN and FRANoIs A. CLOUDMAN, both ofCumberland Mills, county of Cumberland, and State of Maine, haveinvented an Improvement in Apparatus for the Recovery of Soda, of whichthe following description, in connection with the accompanying drawings,is a specification, like letters onthe drawings representing like IOparts.

This invention relates to an apparatus or furnace for reclaimingchemicals from the spent liquors of pulpmill digesters, and is animprovement upon the furnace shown and described in United States PatentNo. 319,956,

dated June 16, 1885. 7

One of the features of our invention consists in providing theevaporating-chamber with, preferably, a series of screw-conveyerslocated near the bottom or hearth of the said chamber, and by means ofwhich the liquid, which in most cases will be of a sirupy consistencywhen it reaches the bottom of the said chamber, may be fed forwardtoward the inlet 2 5 to the rotary calcining or incinerating furnace.

Our invention further consists in providing the rotary calcining-furnacewith an agitating device, herein shown as a screw-conveyor or worm, bymeans of which the soda or other 3o chemical therein may be detachedfrom the walls of the said furnace, thereby preventing the inner wallsof the furnace from becoming coated or lined with chemicals.

Another feature of our invention consists in providing thecombustion-furnace, near the outlet of the calcining-furnace, with athroat having a surrounding water-jacket through which the spent liquoris circulated before entering the evaporating-chamber, the said 7 4ospent liquor serving to somewhat cool the said throat, therebypermitting the latter to be made of iron and to be projected into theoutlet of the rotary calcining-furnace, iron being the most desirablematerial from which 5 to construct the said threat, but which could notbe used to advantage hitherto on account of the intense heat in thefire-chamber, the iron, if used in furnaces made hitherto without thehollow throat having liquid circulating therethrough, being burned outin short time, thereby rendering necessary repairs, which occasioneddelay and expense.

Figure 1 is a longitudinal section of our improved apparatus forreclaiming chemicals in spent liquors from pulp-digesters; Fig. 2, asection on line m as, Fig. 1; and Fig. 3, a sectional detail showingthe'form of the waterjacketed iron throat, the section being taken onthe line 00' as, looking toward the right. 7

The rotary calcining-furnace A, provided 6: with tracks a, running onpulleys a and located between the evaporating-chamber A and thecombustion-furnace A is substantially as shown and described in thepatent referred to.

The combustion-furnace A constructed in the main of brick or otherrefractory material, is provided with a throat, a made of iron,andhaving a surrounding water-jacket, a substantially as shown in Figs. 1and 3, the said iron throat projecting into the axial outlet b 7o of thecalcining-furnace, and being shaped as a segment of a circle to form forthe product in the calcining-f'iu'nace a discharge-passage between thechord b of the segment and the axial outlet 1) of the saidcalcining-furnace, as 7 5 shown in Fig. 3, and described in theabovementioned patent. The iron throat a has connected to itswater-jacket near its bottom a pipe, a communicating, as shown, with thebottom of a tank or reservoir, 13, to contain spent liquor, the saidiron throat also having connected to its water-jacket near its top apipe, 0,, extended into the evaporating-chamber A, the said pipe (1being shown as extended to near the rear wall of the said evap- 8 5crating-chamber. The spent liquor containing the chemicals to berecovered flows from the tank B through the pipe a into the waterjacketof the iron throat, fromwhich it passes through the pipe ainto theevaporating-cham- 0 her, it falling upon a tray, 5 and thence upon asecond tray, 1), arranged zigzag to cause the liquor to pass overalargeevaporating surface, thesaid liquor descending from the tray bupon the bottom of the evaporatingchamber. As 5 theliquor circulatesaround the water-jacketed iron throat,it is heated, and the iron of thesaid throat is cooled sufficiently to prevent it from being burned out.

The liquid issuing from the pipe a is heated 10o on its passage aroundthe iron throat from its water-jacket, so that it readily yields up itswater as it flows through the chamber A, thereby hastening theevaporation of the said liquid, so that when it reaches the bottom ofthe said evaporatingchamber it is substantially of a sirupy consistency.

The sirupy liquid on the bottom of the evaporating-chamber is fedforward from its rear end toward the discharge or outlet 0 of the saidchamber by means of screw-conveyers c, driven by a belt, (not shown,)but which is passed about pulleys 0 at one end of the saidscrew-conveyers outsidetheevaporating-chamber.

The discharge or outlet passage 0 is'controlled by a valve or gate, (notshow-n,) in substantiallythe same manner as in the patent-referred to.

The sirupy liquid fed into the rotary chamberA is calcined therein; andin order to prevent the soda or other chemical salts from adhering tothe inner walls of the said calciningfurnace an agitating device islocated therein.

The agitation device is herein shown as a screw-conveyer or worm, d,which is independent of the calcining-chamber and is free to movetherein.

The screw-conveyer or worm d normally rests upon the bottom of thecalcining-furnace, and as the latter is rotated the said screw-conveyeror worm is carried up on one revolution to a certain distance, when itfalls back again.

The screw-conveyer or worm serves to out off or detach the soda orchemical salt adhering to the inner wall of the calcining-furnace, thesaid screW-conveyer or worm at the same time feeding the soda or otherchemical salt in the furnace forward toward the outlet, the said soda orother chemical salt passing from the calcining-furnace between the chordb and axial outlet 1) and into a suitable receptacle (not shown) locatedbeneath the said discharge or outlet; or the said soda may be dischargeddirectly upon the floor.

The soda or other chemical salt in the calcining-furnace is freed fromorganic matter, which is burned off by the products of combustion fromthe furnace A, they passing through the calcining and the evaporatingfurnaces to the chimney. (Not shown.)

Instead of the screw-conveyer or worm d, we may employ any otheragitating or detaching device, such, for instance, as a harrow providedwith teeth to scrape the adhering salt from the walls of the furnace;

The combustion-furnace may be made stationary or movable with respect tothe calcining-furnace, as desired.

As shown in Figs. 2 and 3, the chord b is made in two parts, forming anangle between them to enable the water leg or throat to be more clearlyshown; but in practice the chord will preferably consist of but a singlestraight line or part.

We claim 1. In an apparatus for recovering chemicals from the spentliquors of pulp-digesters, the

3. In an apparatus forrecovering chemicals I from the spentliquors ofpulp-digesters, a rotary calcining-furnace, a combustionfurnace providedwith an iron throat having a surrounding water-jacket and extended intothe calcining-furnace, and a tank, B, connected to the said jacketedthroat, combined with an evaporating chamber, also connected with thesaidjacketed throat, the spentliquors being circulated around and heatedin the jacketed throat before entering the evaporating-chamber,substantially as described.

4.. I In an apparatus for recovering chemicals from the spent liquors ofpulp-digesters, a rotary calciningfurnace, and a combustion-furnaceprovided with a water-jacketed iron throat extended into thecalcining-furnace, combined with an evaporatingchamber provided withscrew-conveyerslocated near the bottom thereof to feed the chemicalsforward toward the calcining-furnace, substantially as described.

5. In an apparatus for recovering chemicals from the spent liquors ofpulp-digesters, a rotary calciningfurnace, an independent agitat ingdevice located therein, and a combustionfurnace provided with an ironthroat extended into the calcining-furnace, and having asurroundingjacket, combined with an evaporating-chamber provided withscrew-conveyers located near the bottom thereof to feed the chemicalsforward toward the calcining-furnace, substantially as described.

ICC

IIO

6. In an apparatus for recovering chemicals from the spent liquors ofpulp digesters, the combination, with a rotary calcining-furnace, of acombustion-furnace provided with a metallic throat extended intothe'rotary calcining-fnrnace,said throat being surrounded with a hollowjacket adapted to contain a fluid, as and for the purpose specified. v

In testimony whereof we have signed our names to this specification inthe two subscribing witnesses.

JOHN E. WARREN. FRANCIS A. OLOUDMAN.

Witnesses:

FRED. S. VERRILL, WV. E. AYER.

presence of

